One of them says he'd like to bring nuclear weapons to the border. Another vows to stop the alleged Mexican invasion of Idaho. Several have links to white supremacist hate groups; others are given to dire warnings of horrible diseases, "barbaric" practices, and secret Latino conspiracies to "reconquer" the American Southwest. These are the nativists -- the new crop of activists who are driving the movement that exploded last spring with the Minuteman Project in Arizona, a month-long effort by armed civilians to seal the border with Mexico. Along with a whole array of media enablers (see Broken Record and Nativism On Air), they have barged into the nation's consciousness with remarkable success. Some of them, like Minuteman co-founder Jim Gilchrist, have made attempts to win high political office. Others have contented themselves with trying to build a mass movement. Not all those who have joined the movement are extremists -- many are legitimately concerned about the ability of the nation to absorb large numbers of immigrants, particularly the undocumented. But one thing seems clear: A dangerous mix of nativist intolerance, armed and untrained civilians, and wild-eyed conspiracy theories could easily explode into violence.